Search Results

Search found 21089 results on 844 pages for 'virtual memory'.

Page 312/844 | < Previous Page | 308 309 310 311 312 313 314 315 316 317 318 319  | Next Page >

• non-scalar type requested

  - by lego69

  can somebody please help me with an error conversion from `A' to non-scalar type `B' requested I have class A and derived from it B, but I have problems with these rows: A a(1); A *pb = new B(a); B b = *pb; //here I have an error thanks in advance for any help class A { protected: int player; public: A(int initPlayer = 0); A(const A&); A& operator=(const A&); virtual ~A(){}; virtual void foo(); void foo() const; operator int(); }; class B: public A { public: B(int initPlayer): A(initPlayer){}; ~B(){}; virtual void foo(); };

  Read the article

• c++: strange syntax in what() method of std::exception

  - by Patrick Oscity

  When i am inheriting from std::exception in order to define my own exception type, i need to override the what() method, which has the following signature: virtual const char* what() const throw(); This definitely looks strange to me, like if there were two method names in the signature. Is this some very specific syntax, like with pure virtual methods, e.g.: virtual int method() const = 0; or is this a feature, that could somehow be used in another context, too? And if so, for what could it be used?

  Read the article

• Multiple interfaces inhertience. Casting from one to another

  - by yossi1981

  Consider the following set of classes/Interfaces: class IFish{ public: virtual void eat() = 0; } class IFriendly{ public: virtual void protect() = 0; } class IAggresive{ public: virtual void attack(Point inDest) = 0; } class CDolphin : public IFish, IFriendly{ eat... protect.... } class CShark : public IFish, IAggresive{ eat.... attack... } Now I am having the following class void CDiver { Void shouldRunAway(IFish* fish) { //??? } } My question is , can "shouldRunAway" extract from the fish argument whether it is an IAggresive or IFreindly (if it is any of these at all...) is there some kind of casting that can help out?

  Read the article

• Make sure base method gets called in C#

  - by Fnatte

  Can I somehow force a derived class to always call the overridden methods base? public class BaseClass { public virtual void Update() { if(condition) { throw new Exception("..."); // Prevent derived method to be called } } } And then in a derived class : public override void Update() { base.Update(); // Forced call // Do any work } I've searched and found a suggestion to use a non-virtual Update() but also a protected virtual UpdateEx(). It just doesn't feel very neat, isn't there any better way? I hope you get the question and I am sorry for any bad English.

  Read the article

• C++ Singleton design pattern.

  - by Artem Barger

  Recently I've bumped into realization/implementation of Singleton design pattern for C++. It has looked in the following way (I have adopted it from real life example): // a lot of methods is omitted here class Singleton { public: static Singleton* getInstance( ); ~Singleton( ); private: Singleton( ); static Singleton* instance; }; From this declaration I can deduce that instance field is initiated on the heap, that means there is a memory allocation. That is completely unclear for me is when does exactly memory is going to be deallocated? Or there is a bug and memory leak? It seems like there is a problem in implementation. PS. And main question how to implement it in the right way?

  Read the article

• STL deque accessing by index is O(1)?

  - by jasonline

  I've read that accessing elements by position index can be done in constant time in a STL deque. As far as I know, elements in a deque may be stored in several non-contiguous locations, eliminating safe access through pointer arithmetic. For example: abc-defghi-jkl-mnop The elements of the deque above consists of a single character. The set of characters in one group indicate it is allocated in contiguous memory (e.g. abc is in a single block of memory, defhi is located in another block of memory, etc.). Can anyone explain how accessing by position index can be done in constant time, especially if the element to be accessed is in the second block? Or does a deque have a pointer to the group of blocks? Update: Or is there any other common implementation for a deque?

  Read the article

• Const Functions and Interfaces in C++

  - by 58gh1z

  I'll use the following (trivial) interface as an example: struct IObject { virtual ~IObject() {} virtual std::string GetName() const = 0; virtual void ChangeState() = 0; }; Logic dictates that GetName should be a const member function while ChangeState shouldn't. All code that I've seen so far doesn't follow this logic, though. That is, GetName in the example above wouldn't be marked as a const member function. Is this laziness/carelessness or is there a legitimate reason for this? What are the major cons of me forcing my clients to implement const member functions when they are logically called for?

  Read the article

• c++ programming for clusters and HPC

  - by Abruzzo Forte e Gentile

  HI All I need to write a scientific application in C++ doing a lot of computations and using a lot of memory. I have part of the job but due to high requirements in terms of resources I was thinking to start moving to OpenMPI. Before doing that I have a simple curiosity: If I understood the principle of OpenMPI is the developer that has the task of splitting the jobs over different nodes calling SEND and RECEIVE based on node available at that time. Do you know if it does exist some library or OS or whatever that has this capability letting my code reamain as it is now? Basically something that connects all computers and let share as one their memory and CPU? I am a bit confused because of the high material available on the topic. Should I look at cloud computing? or Distributed Shared Memory? Can you help me or address me a bit? Thanks

  Read the article

• "Access violation reading location" troubles retrieveing buffer from directx

  - by numerical25

  Below is my code... ID3D10Texture2D *pBackBuffer; hr = mpSwapChain->GetBuffer(0, __uuidof(ID3D10Texture2D), (LPVOID*) &pBackBuffer); and I get the following error chp1.exe': Unloaded 'C:\Windows\SysWOW64\oleaut32.dll' First-chance exception at 0x757ce124 in chp1.exe: Microsoft C++ exception: _com_error at memory location 0x0018eeb0.. First-chance exception at 0x757ce124 in chp1.exe: Microsoft C++ exception: _com_error at memory location 0x0018edd0.. First-chance exception at 0x757ce124 in chp1.exe: Microsoft C++ exception: _com_error at memory location 0x0018ef1c.. The thread 'Win32 Thread' (0xfc4) has exited with code 0 (0x0). 'chp1.exe': Unloaded 'C:\Windows\SysWOW64\D3D10Ref.DLL' First-chance exception at 0x00b71894 in chp1.exe: 0xC0000005: Access violation reading location 0x00000000. Unhandled ex ception at 0x00b71894 in chp1.exe: 0xC0000005: Access violation reading location 0x00000000. It appears that the error occurs in the last parameter. &pBackBuffer. I added this single line of code and the error occurs.

  Read the article

• Select from parent table return ID = 0 column values for child objects

  - by SaD

  Entities: public class Person { public Person(){} public virtual long ID { get; set; } } public class Employee : Person { public Employee(){} public virtual long ID { get; set; } public virtual string Appointment { get; set; } } Mappings: public class PersonMap : ClassMap<Person> { public PersonMap() { Id(x => x.ID) .GeneratedBy.Identity(); } } public class EmployeeMap : SubclassMap<Employee> { public EmployeeMap() { KeyColumn("ID"); Map(x => x.Appointment) .Not.Nullable() .Length(50); } } 2 items in Person table 1 item in Employee table (1 in base class, 1 in child class) Query:var list = Session.CreateQuery("from Person").List<Person>(); Return: 0 | ID = 1 1 | ID = 0, Appointment = "SomeAppointment"

  Read the article

• Session Timeout and page response time

  - by Johnny5

  Hi, I'm load testing an asp.net app. The load test is simulating 500 user doing searchs on the site and browsing the results. I'm observing that the more I reduce the session timeout limit (in web.config) the better the page response time. For exemple, with a timeout at 10 minutes, I got an average response time of 8.35 seconds. With a timout at 3 minutes, the average response time for the same page is 3,98 seconds. The session in stored "InProc". I supposed the memory used by the "no more used but still actives" sessions may be in cause. But, even if there is more memory used when the timeout is at 10, there is still plenty of memory available (about 2.7Gb). Any ideas?

  Read the article

• Can I compile and execute C# expression without saving the assembly to disk?

  - by Sasha

  I can compile, get an instance and invoke a method of any C# type programmaticaly. There lots of info on that, including the StackOverflow (http://stackoverflow.com/questions/53844/how-can-i-evaluate-a-c-expression-dynamically). My problem is that I'm in the web environment and cannot save anything to /bin directory. I can compile "in-memory" as the above mentioned link suggests but then I won't be able to "unload" my custom assembly from the current AppDomain. After a while that will become a huge memory problem. Is it possible to open a new AppDomain, compile new assembly "in-memory", evaluate some expression or access some member of that assembly inside of that new AppDomain and kill that AppDomain safely when done, all that without saving anything to a hard drive? Thanks in advance for any links, suggestions, etc.

  Read the article

• How do I keep subdomain.domain.com links from mapping to subdomain.domain.com/subdomain?

  - by Alan Jackson

  I have a virtual directory created and a sub domain that points to that virtual directory. My links always route to subdomain.domain.com/subdomain/controller/action when they can leave off the subdomain link. Is there an easy way to stop that? Also, it's the same problem when I mapped anotherdomain.com to my virtual directory. It ends up linking to anotherdomain.com/virtualdir/controller/action. It just looks unprofessional to me to have all my links be myapp.com/myapp/action/controller.

  Read the article

• Access to bytes array of a Bitmap

  - by Deulis

  1- In Windows CE, I have a Bitmap object in C#. 2- I have a C function in an extern dll that expects as parameters the pointer to a bytes array that represents an image in RGB565 format, width and height. This function will draw on this array of bytes. So I need to pass the byte array pointer of the Bitmap object, but I can find a practical way to get this pointer. One way is convert this Bitmap into a bytes array using a memory stream or something else, but it will create a new bytes array, so I will keep in memory both object, the Bitmap and the bytes array, but I don’t want it because the few available memory, that’s why I need to access to the bytes array of the bitmap object, not create a new bytes array. Anyone can help me?

  Read the article

• Is it possible to load a file full of binary data into GDB when GDB is debugging a core file?

  - by efunneko

  I am debugging a crash using GDB and a core file. A large portion of the memory space is mmapped into the process. That portion of the memory is not saved into the core file. I have a file that contains all the data in that mmapped memory. I would like to find a way to load the data from that file into GDB at a certain offset so that I can display datastructures within that address space. Is this possible? Note that I have tried the 'restore' command in GDB and it does not work when debugging a core file. Perhaps there are tools that allow a core file to have additional data appended to it?

  Read the article

• Which destructor is called when in C++?

  - by BastiBechtold

  I am hunting memory leaks in a program. I narrowed it down to some destructors not being called. However, I can't figure out why: class CMain : public CList { public: CMain(); virtual ~CMain(); ... } class CList : public CProc { public: CList(); virtual ~CList(); ... } CMain gets deallocated just fine, but ~CList() is never called. All parent classes of CList have virtual destructors, too. Do you have any hints about why the destructor for CList is never called?

  Read the article

• static effect on python

  - by fatai

  how we can construct static effect on python instead of using class and global ? not like that one : global a a = [] #simple ex ; fonk ( a , b , d) x = 1 a.append ( x) EDIT: I want to create temporary memory , if I exit the function namely fonk , I want to save change as list on temporary memory . We can do that demand only put static keyword in front of data type but in python , we dont have static, so I want that effect in python . Therefore , how can I do ? As above code say "a" represents temporary memory

  Read the article

• Fluent Nhibernate mapping related items

  - by Josh

  I am trying to relate 2 items. I have a table that is simply an Id field, and then 2 columns for the Item Id's to relate. I want it to be a 2 way relationship - that is, if the items appear twice in the table, I only want one relationship connection back. So, here's my item: public class Item { public virtual Guid ItemId {get; set;} public virtual string Name {get; set;} public virtual IList<Item> RelatedItems {get; set;} } The table for relating the items looks like this: CREATE TABLE RelatedItems ( RelatedItemId uniqueidentifier NOT NULL, ItemId uniqueidentifier NOT NULL, RelatedId uniqueidentifier NOT NULL, CONSTRAINT PK_RelatedItems PRIMARY KEY CLUSTERED (RelatedItemId) ) What is the best way to map this connection?

  Read the article

• C++ Singleton design pattern

  - by Artem Barger

  Recently I've bumped into a realization/implementation of the Singleton design pattern for C++. It has looked like this (I have adopted it from the real life example): // a lot of methods are omitted here class Singleton { public: static Singleton* getInstance( ); ~Singleton( ); private: Singleton( ); static Singleton* instance; }; From this declaration I can deduce that the instance field is initiated on the heap. That means there is a memory allocation. What is completely unclear for me is when exactly the memory is going to be deallocated? Or is there a bug and memory leak? It seems like there is a problem in the implementation. My main question is, how do I implement it in the right way?

  Read the article

• Using sizeof with a dynamically allocated array

  - by robUK

  Hello, gcc 4.4.1 c89 I have the following code snippet: #include <stdlib.h> #include <stdio.h> char *buffer = malloc(10240); /* Check for memory error */ if(!buffer) { fprintf(stderr, "Memory error\n"); return 1; } printf("sizeof(buffer) [ %d ]\n", sizeof(buffer)); However, the sizeof(buffer) always prints 4. I know that a char* is only 4 bytes. However, I have allocated the memory for 10kb. So shouldn't the size be 10240? I am wondering am I thinking right here? Many thanks for any suggestions,

  Read the article

• How is the implicit segment register of a near pointer determined?

  - by Daniel Trebbien

  In section 4.3 of Intel 64® and IA-32 Architectures Software Developer's Manual. Volume 1: Basic Architecture, it says: A near pointer is a 32-bit offset ... within a segment. Near pointers are used for all memory references in a flat memory model or for references in a segmented model where the identity of the segment being accessed is implied. This leads me to wondering: how is the implied segment register determined? I know that (%eip) and displaced (%eip) (e.g. -4(%eip)) addresses use %cs by default, and that (%esp) and displaced (%esp) addresses use %ss, but what about (%eax), (%edx), (%edi), (%ebp) etc., and can the implicit segment register depend also on the instruction that the memory address operand appears in?

  Read the article

• Secure way to run other people code (sandbox) on my server?

  - by amikazmi

  I want to make a web service that run other people code locally... Naturally, I want to limit their code access to certain "sandbox" directory, and that they wont be able to connect to other parts of my server (DB, main webserver, etc) Whats the best way to do it? Run VMware/Virtualbox: (+) I guess it's as secure as it gets.. even if someone manage to "hack".. they only hack the guest machine (+) can limit the cpu & memory the process uses (+) easy to setup.. just create the VM (-) harder to "connect" the sandbox directory from the host to the guest (-) wasting extra memory and cpu for managing the VM Run underprivileged user: (+) doesnt waste extra resources (+) sandbox directory is just a plain directory (?) cant limit cpu and memory? (?) dont know if it's secure enough... Any other way? Server running Fedora Core 8, the "other" codes written in Java & C++

  Read the article

• Can I play any Buffer only once at a given time?

  - by mystify

  From the OpenAL documentation: The basic OpenAL objects are a Listener, a Source, and a Buffer. There can be a large number of Buffers, which contain audio data. Each buffer can be attached to one or more Sources My problem is, that I have one sound file which I need to play multiple times per second, at the same time. The sound is 2 seconds long. So it will overlap. Would I need multiple filled buffers for this (= multiple times that sound in memory)? If I would attach one Buffer to multiple Sources, would I be able to play the sound 10 times, overlapping itself, with just one copy in memory? Or would I still have to deal with 10 copies of that sound in memory?

  Read the article

• Destructors for C++ Interface-like classes

  - by sdg

  Starting to use PC-Lint on an existing code base (fear and trepidation). One thing that it complains about is the following: class IBatch { public: virtual void StartBatch() =0; virtual int CommitBatch() =0; }; Which when another class derives from this to use it like an interface base class 'IBatch' has no destructor So, the question: when you create Interface classes like the above, do you always include a virtual destructor? Why? (is it a style or a coding error?)

  Read the article

• What's the outcome if I use free with new or delete with malloc?

  - by skydoor

  It is a compiler error or runtime error? The code below can be compiled! class Base{ void g(); void h(); }; int main() { Base* p = new Base(); free(p); return 0; } However it can't be compiled with a virtual function if I declare the class Base like this class Base{ virtual void g(); void h(); }; The code below can be compiled all the time, no matter the function is virtual or not. class Base{ void g(); void h(); }; int main() { Base* p = (Base*)malloc(sizeof(Base)); delete p; return 0; }

  Read the article

< Previous Page | 308 309 310 311 312 313 314 315 316 317 318 319  | Next Page >